Microbiology 38

Which of the following diseases occurring in the United States lacks a known insect vector? (A) Hantavirus pulmonary syndrome (B) West Nile fever (C) La Crosse encephalitis (D) Colorado tick fever (E) St. Louis encephalitis

(A) Hantavirus pulmonary syndrome

African hemorrhagic fevers, Marburg and Ebola, are severe diseases often ending in death. Which of the following is most accurate about Ebola virus? (A) It is spread by contact with blood or other body fluids. (B) It is transmitted by mosquitoes. (C) It is a flavivirus. (D) It causes infections but no disease in nonhuman primates. (E) It is antigenically related to Lassa fever virus.

(A) It is spread by contact with blood or other body fluids.

14. Which of the following statements about yellow fever is false? (A) There is no animal reservoir. (B) The name "yellow" comes from the fact that many victims have jaundice. (C) Certain mosquitoes are biological hosts for the causative agent. (D) Outbreaks of the disease could occur in the United States because a suitable vector is present. (E) An attenuated vaccine is widely used to prevent the disease.

(A) There is no animal reservoir.

Regarding the patient in Question 5, yellow fever occurs in which region or regions of the world? (A) Asia (B) Africa and South America (C) North America (D) Africa and Middle East (E) Throughout the world

(B) Africa and South America

A 27-year-old man develops fever, chills, headache, and backache. Four days later he develops a high fever and jaundice. Yellow fever is diagnosed. Which of the following statements concerning yellow fever is correct? (A) The virus is transmitted by culicine mosquitoes in the urban form of disease. (B) Monkeys in the jungle are a major reservoir of yellow fever virus. (C) Yellow fever often has long-term complications. (D) All infections lead to apparent disease. (E) Ribavirin is specific therapy.

(B) Monkeys in the jungle are a major reservoir of yellow fever virus.

Hantaviruses, which are emerging pathogens in the United States, can be described by which of the following? (A) They are arenaviruses. (B) They are readily transmitted human to human. (C) They cause influenza-like symptoms followed rapidly by acute respiratory failure. (D) They are acquired by inhalation of aerosols of deer urine. (E) They show a high frequency of antigenic variation.

(C) They cause influenza-like symptoms followed rapidly by acute respiratory failure.

Which of the following statements about hantaviruses in the United States is correct? (A) They are limited in range to southwestern states. (B) They are carried only by deer mice. (C) They infect human beings with a fatality rate that can be above 30%. (D) They were first identified in the early 1970s. (E) They are contracted mainly in bat caves.

(C) They infect human beings with a fatality rate that can be above 30%.

Each of the following statements concerning arboviruses is correct except (A) The pathogenesis of dengue hemorrhagic shock syndrome is associated with the heterotypic anamnestic response. (B) Wild birds are the reservoir for encephalitis viruses but not for yellow fever virus. (C) Ticks are the main mode of transmission for both encephalitis viruses and yellow fever virus. (D) There is a live, attenuated vaccine that effectively prevents yellow fever.

(C) Ticks are the main mode of transmission for both encephalitis viruses and yellow fever virus.

A microbiologist was performing a necropsy in a laminar flow biosafety cabinet on a blue-jay submitted as part of a state's arbovirus surveillance program. He lacerated his thumb while using a scalpel to remove the bird's brain. Four days later, he developed a headache, myalgia, and malaise followed by chills, sweats, and lymph node swelling. Two days later, a rash began on his face and spread to the trunk, arms, and legs, persisting for about 3 days. He sought medical care and reported a history of dengue fever and vaccinations with yellow fever and Japanese B encephalitis vaccines. A serum sample taken the day of the injury contained anti-flavivirus immunoglobulin G (IgG) antibody by enzyme-linked immunosorbent assay. A serum sample collected 13 days after the onset of illness showed an increased titer of antiflavivirus IgG antibody and the presence of West Nile virus IgM antibody. The physician could conclude that the most likely cause of the microbiologist's illness was which virus? (A) Dengue virus (B) Yellow fever virus (C) West Nile virus (D) St. Louis encephalitis (E) Not identifiable until neutralizing antibody titers from paired sera could be assessed against a panel of arboviruses

(C) West Nile virus

An arbovirus common in the Middle East, Africa, and Southwest Asia first appeared in New York in 1999. By 2002 the virus had spread throughout the continental United States. This arbovirus, a member of the Japanese B encephalitis antigenic complex, is which of the following? (A) Japanese B encephalitis virus (B) Tick-borne encephalitis virus (C) West Nile virus (D) Dengue virus (E) Rift Valley fever virus

(C) West Nile virus

Which of the following descriptions of or statements about Lassa fever is correct? (A) It is found in eastern Africa. (B) Human-to-human transmission does not occur. (C) It seldom causes death or complications. (D) It occurs from contact with the house rat Mastomys natalensis. (E) There is no drug that is effective in treating Lassa fever.

(D) It occurs from contact with the house rat Mastomys natalensis.

A 74-year-old man develops fever, malaise, and a sore throat followed shortly thereafter by nausea, vomiting, and then stupor. Eastern equine encephalitis is diagnosed. Control of this disease in humans could be accomplished by eradication of which of the following? (A) Horses (B) Birds (C) Sandflies (D) Mosquitoes (E) Ticks

(D) Mosquitoes

Which of the following statements about dengue virus is not true? (A) It is the most important mosquito-borne viral disease affecting humans. (B) It is distributed worldwide in tropical regions. (C) It can cause a severe hemorrhagic fever. (D) There is a single antigenic type. (E) One form of disease is characterized by increased vascular permeability.

(D) There is a single antigenic type.

Arboviruses are transmitted by bloodsucking arthropods from one vertebrate host to another. Arboviruses are found in the following virus families except which of the following? (A) Togaviridae (B) Flaviviridae (C) Bunyaviridae (D) Reoviridae (E) Arenaviridae

(E) Arenaviridae

Which of the following groups can be vaccinated routinely with yellow fever vaccine without special safety considerations? (A) Children younger than 9 months old (B) Pregnant women (C) Persons with compromised immune systems (D) All of the above (E) None of the above

(E) None of the above